For those who still do not know, memory foam – visco-elastic mattress is made – is simply polyurethane with additional components that increase the density and viscosity. Developed under the NASA space program, it is now important for civilian use, especially for people with illnesses that require appropriate support for back and neck. Think of bedridden patients sleep apnea and in patients with fibromyalgia individuals.Even and healthy individuals with little or no back problems will benefit from the comfort of a visco-elastic mattress.